This invention relates in general to gas detection methods and equipment, and in particular relates to the detection of gas absorbed in a body liquid, such as gases which are formed in oil-filled electrical apparatus.
Oil filled electrical apparatus such as electrical transformers in many instances generate gases from faults or failures in the apparatus. For example, electrical arcing and discharge, overheating, breakdown of cellulosic paper or heating of copper bus bars within oil will produce gases such as hydrogen, carbon monoxide and carbon dioxide.
It has heretofore been known to analyze the gases in oil-filled electrical apparatus to indicate the presence and nature of incipient faults of the foregoing character. One method which has been employed for this purpose is to periodically drain an oil sample from the transformer or other apparatus into containers, with the gases then being extracted from the sample by vacuum. The extracted gases are then passed through a chromatograph for analysis. Another recipient fault detection system includes equipment which automatically and periodically drains oil from a transformer into a chamber from which gas is extracted and analyzed in a chromatograph, but such equipment is complicated in design and construction and is relatively expensive. Mechanical apparatus has also been employed to pump oil from a transformer through a gas permeation cell. However, the moving parts required in apparatus of this character introduce wear and maintenance problems and are a source of malfunction. It would be desirable to provide a system which will extract gas from a body of liquid continuously without the requirement for moving parts, and without the need for a separate power source.